hydra: Add job to run "make distcheck" on Guix.

* build-aux/hydra/guix.scm: New file.
* Makefile.am (EXTRA_DIST): Add it.

Makefile.am

@@ -142,6 +142,7 @@ EXTRA_DIST =					\
   TODO						\
   .dir-locals.el				\
   build-aux/hydra/gnu-system.scm		\
+  build-aux/hydra/guix.scm			\
   build-aux/check-available-binaries.scm	\
   build-aux/download.scm			\
   build-aux/list-packages.scm			\

build-aux/hydra/guix.scm

@@ -0,0 +1,98 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2013 Ludovic Courtès <ludo@gnu.org>
+;;;
+;;; This file is part of GNU Guix.
+;;;
+;;; GNU Guix is free software; you can redistribute it and/or modify it
+;;; under the terms of the GNU General Public License as published by
+;;; the Free Software Foundation; either version 3 of the License, or (at
+;;; your option) any later version.
+;;;
+;;; GNU Guix is distributed in the hope that it will be useful, but
+;;; WITHOUT ANY WARRANTY; without even the implied warranty of
+;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;;; GNU General Public License for more details.
+;;;
+;;; You should have received a copy of the GNU General Public License
+;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
+
+;;;
+;;; This file defines build jobs of Guix itself for the Hydra continuation
+;;; integration tool.
+;;;
+
+;; Attempt to use our very own Guix modules.
+(eval-when (compile load eval)
+
+  ;; Ignore any available .go, and force recompilation.  This is because our
+  ;; checkout in the store has mtime set to the epoch, and thus .go files look
+  ;; newer, even though they may not correspond.
+  (set! %fresh-auto-compile #t)
+
+  (and=> (assoc-ref (current-source-location) 'filename)
+         (lambda (file)
+           (let ((dir (string-append (dirname file) "/../..")))
+             (format (current-error-port) "prepending ~s to the load path~%"
+                     dir)
+             (set! %load-path (cons dir %load-path))))))
+
+
+(use-modules (guix store)
+             (guix packages)
+             (guix utils)
+             (guix build-system gnu)
+             (gnu packages package-management)
+             (srfi srfi-1)
+             (ice-9 match))
+
+;; XXX: Debugging hack: since `hydra-eval-guile-jobs' redirects the output
+;; port to the bit bucket, let us write to the error port instead.
+(setvbuf (current-error-port) _IOLBF)
+(set-current-output-port (current-error-port))
+
+(define* (package->alist store package system
+                         #:optional (package-derivation package-derivation))
+  "Convert PACKAGE to an alist suitable for Hydra."
+  `((derivation . ,(package-derivation store package system))
+    (description . ,(package-synopsis package))
+    (long-description . ,(package-description package))
+    (license . ,(package-license package))
+    (home-page . ,(package-home-page package))
+    (maintainers . ("bug-guix@gnu.org"))))
+
+(define (tarball-package checkout)
+  "Return a package that does `make distcheck' from CHECKOUT, a directory
+containing a Git checkout of Guix."
+  (let ((dist (dist-package guix checkout)))
+    (package (inherit dist)
+      (location (source-properties->location (current-source-location)))
+      (arguments (substitute-keyword-arguments (package-arguments dist)
+                   ((#:phases p)
+                    `(alist-cons-before
+                      'autoreconf 'patch-bootstrap-script
+                      (lambda _
+                        ;; Comment out `git' invocations, since Hydra provides
+                        ;; us with a checkout that includes sub-modules.
+                        (substitute* "bootstrap"
+                          (("git submodule init")
+                           "true\n")))
+                      ,p)))))))
+
+(define (hydra-jobs store arguments)
+  "Return Hydra jobs."
+  (define systems
+    (match (filter-map (match-lambda
+                        (('system . value)
+                         value)
+                        (_ #f))
+                       arguments)
+      ((lst ..1)
+       lst)
+      (_
+       (list (%current-system)))))
+
+  (define checkout
+    (assq-ref arguments 'guix))
+
+  `((tarball . ,(package->alist store (tarball-package checkout)
+                                (%current-system)))))